Electronic devices that rely on the close matching of electronic components (e.g., resistors, capacitors, etc.) or precision in one or more signals provided by an electronic component may be vulnerable to errors caused by tolerances inherent in the manufacture of the components. Calibration is often performed on a device to reduce or eliminate these errors. The term “calibrate” refers generally to any modification to a signal and/or electronic component to provide correction and/or compensation. For example, calibration may include adjusting one or more signals to correct for component mismatch errors.
Analog-to-digital converters (ADC), for example, often employ one or more sample and hold circuits that rely on matched capacitors to accurately determine the level or value of an analog input signal. The precision of an ADC may depend on capacitors that exhibit essentially identical operating characteristics. However, variability in manufacturing processes of the capacitors may produce slightly different properties and characteristics. Such imperfectly matched components may provide one or more signals having errors in proportion to the mismatch. Moreover, various electronic devices may rely on precise voltages, currents or comparisons thereof provided by electronic components that vary with process, temperature, frequency, power supply, etc. To achieve a desired device performance, one or more of these errors may require correction by calibrating one or more signals of the device.
Calibrating an electronic device may be achieved by correcting signals generated by one or more digital or analog components in the device. For example, calibration values may be stored in a device and referenced during operation of the device to correct for errors in signals provided by or operated on by the device. A memory may be provided to store calibration bits (also referred to as calibration coefficients) that are added, subtracted or otherwise employed to adjust the value of one or more signals. Calibration bits may be stored via a plurality of fuses that are selectively blown to store, for example, a value of 0 when disconnected (i.e., open circuit condition) and a value of 1 when fused (i.e., short circuit condition). A plurality of fuses may be employed to represent a desired number, value or code that can be used to calibrate one or more signals of a device. Alternatively, any other type of memory device may be used to store calibration bits.
The greater the number of fuses arranged to store a calibration value, or the greater the word length of a calibration coefficient stored in other types of memory, the more precisely a signal may be calibrated. However, increasing the number of fuses (and/or increasing the size of the memory) increases the size of the device, for example, by increasing the die area of an integrated circuit. In addition, the larger the memory, the more power the device consumes. For example, each fuse requires additional power consumption to test whether the fuse has been blown or not (i.e., to test whether a respective fuse stores a 0 value or a 1 value). As a result, there is often a tradeoff between die area and power consumption, and the resolution at which a device may be calibrated.